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Community Detection with the Weighted Parsimony Criterion

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Journal of Systems Science & Complexity 2015年第3期28卷 517-545页

作者： BETTINELLI andrea HANSEN Pierre LIBERTI Leo Dipartimento di Ingegneria dell’Energia Elettrica e Dell’Informazione Università di Bologna Viale del Risorgimento 2 40136 Bologna Italy Groupe d’études et de Recherche en Analyse des Décisions Hautes tudes Commerciales Montréal Canada LIX cole Polytechnique F-91128 Palaiseau France CNRS LIX Ecole Polytechnique 91128 Palaiseau France

Community detection in networks has been studied extensively in the last decade. Many criteria, expressing the quality of the partitions obtained, as well as a few exact algorithms and a large number of heuristics have been proposed. The parsimony criterion consists in minimizing the number of edges added or removed from the given network in order to transform it into a set of disjoint *** Zhang, Qiu and Zhang have proposed a weighted parsimony model in which a weight coefficient is introduced to balance the numbers of inserted and deleted edges. These authors propose rules to select a good value of the coefficient, use simulated annealing to find optimal or near-optimal solutions and solve a series of real and artificial instances. In the present paper, an algorithm is proposed for solving exactly the weighted parsimony problem for all values of the parameter. This algorithm is based on iteratively solving the problem for a set of given values of the parameter using a row generation algorithm. This procedure is combined with a search procedure to find all lowest breakpoints of the value curve(i.e., the weighted sum of inserted and deleted edges). Computational results on a series of artificial and real world networks from the literature are reported. It appears that several partitions for the same network may be informative and that the set of solutions usually contains at least one intuitively appealing partition.

关键词： Community detection complex networks parsimony.

Advanced methodologies for the cleaning of works of art

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Science China(Technological Sciences) 2023年第8期66卷 2162-2182页

作者： CASINI andrea CHELAZZI David BAGLIONI Piero CSGI and Department of Chemistry“Ugo Schiff” University of FlorenceSesto FiorentinoFlorence 50019Italy Department of Chemistry“Ugo Schiff”and CSGI University of FlorenceSesto FiorentinoFlorence 50019Italy

Cultural heritage assets constitute a fundamental socioeconomic resource,but the actual works of art need to be maintained,counteracting degradation processes,to transfer these benefits to future *** particular,the removal of soil,aged coatings,and vandalism/overpaints is one of the most needed interventions in art *** cleaning methodologies,based on classical solution and polymer chemistry,only grant limited control of the cleaning interventions,with the risk of affecting the original components of the artifacts,and often involving the use of toxic or non-environmentally friendly ***,materials science,colloids,and soft matter have provided valuable and safe solutions in the last *** review provides a selection of the most recent and advanced methodologies for the wet cleaning of works of art,spanning from nanostructured cleaning fluids(microemulsions,surfactants swollen micelles)to physical and chemical *** new methodologies work on different physico-chemical mechanisms,such as processes for detaching/dewetting,to selectively remove the unwanted layers in sustainable and cost-effective *** best performing systems,like microemulsions confined in“twin-chain”polyvinyl alcohol gels,have been assessed in the cleaning of masterpieces such as works by Pablo Picasso,Jackson Pollock and Roy *** attention is dedicated to“green”chemistry systems,using low-toxicity solvents or bio-based/waste materials to build gel ***,current trends and future perspectives are given,showing that advanced systems for art cleaning link with transversal fields of crucial importance even beyond Cultural heritage conservation,e.g.,detergency,tissue engineering,drug-delivery,food industry and cosmetics.

关键词： cleaning conservation cultural heritage gels microemulsions surfactants colloids nanoscience

Seismic displacement demand prediction in non-linear domain: Optimization of the N2 method

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 141-158页

作者： Lorenzo Diana andrea Manno Pierino Lestuzzi EPFL – ENAC – IIC – IMAC DEIB Politecnico di Milano

In Europe, computation of displacement demand for seismic assessment of existing buildings is essentially based on a simplified formulation of the N2 method as prescribed by Eurocode 8(EC8). However, a lack of accuracy of the N2 method in certain conditions has been pointed out by several studies. This paper addresses the assessment of effectiveness of the N2 method in seismic displacement demand determination in non-linear domain. The objective of this work is to investigate the accuracy of the N2 method through comparison with displacement demands computed using non-linear timehistory analysis(NLTHA). Results show that the original N2 method may lead to overestimation or underestimation of displacement demand predictions. This may affect results of mechanical model-based assessment of seismic vulnerability at an urban scale. Hence, the second part of this paper addresses an improvement of the N2 method formula by empirical evaluation of NLTHA results based on EC8 ground-classes. This task is formulated as a mathematical programming problem in which coefficients are obtained by minimizing the overall discrepancy between NLTHA and modified formula results. Various settings of the mathematical programming problem have been solved using a global optimization metaheuristic. An extensive comparison between the original N2 method formulation and optimized formulae highlights benefits of the strategy.

关键词： N2 method seismic vulnerability assessment non-linear time-history analysis spectrum compatible recordings displacement demand determination optimization strength reduction factor

Effect of grassland mosaic structure and dynamism on the reproductive habitat suitability for Alectoris graeca in central Apennines

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Journal of Mountain Science 2019年第12期16卷 2783-2792页

作者： andrea BRUSAFERRO Valentina IESARI Federico Maria TARDELLA Paola SCOCCO andrea CATORCI School of Biosciences and Veterinary Medicine University of Camerino

Over the last several decades,the Mediterranean region has been subjected to mountain abandonment and farming cessation,leading to changes in vegetation and coenological features of grasslands,contextually to the strong decline of the rock partridge(Alectoris graeca).Our hypothesis was that the ongoing dynamic processes leading to the compositional changes of grasslands in central Apennines affect the habitat suitability for the singing male(territorial male defending its reproductive site).In 2015,we defined the presence/absence of spring territorial singing males in seven sites(1,250-2,400 m a.s.l.),by the census in 74 playback stations,distributed along 15 *** characterized the topography and the vegetation mosaic of such sites according to the collected topographic and vegetation cover data in 59 randomly selected plots(100 m×100 m)along the *** understand the relations among the environmental variables and the effect of the composition and dynamism of the vegetation mosaics on the presence/absence of the singing male,we used principal components analysis and generalized linear mixed-effect *** results emphasized the marked overlap between the general environmental conditions,which proved to define the habitat suitability for ***,and the characteristics of the site chosen by the singing male for starting the reproductive ***,we found that the site suitability for the singing male decreases when the vegetation recovery processes are ongoing,because of the spread of coarse tall grassesdominated communities and/or grassland types with dense *** grass-dominated communities and thick-turf grasslands exert their negative effect decreasing the habitat suitability for the singing male starting from low cover ***,it is conceivable that singing male’s suitable habitat will be dramatically restricted to the steepest south-facing slopes,where topographic and soil conditions do not allow the spread of grassl

关键词： Brachypodium genuense Grazing cessation Reproductive habitat suitability Rock partridge Singing male Vegetation recovery processes

SRAM-Based FPGA Systems for Safety-Critical Applications： A Survey on Design Standards and Proposed Methodologies

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Journal of Computer Science & Technology 2015年第2期30卷 373-390页

作者： Cinzia Bernardeschi Luca Cassano andrea Domenici Department of Information Engineering University of Pisa Pisa 56122 Italy Dipartimento di Elettronica Informazione e Bioingegneria Politecnico di Milano Milano 20133 Italy

As the ASIC design cost becomes affordable only for very large-scale productions, the FPGA technology is currently becoming the leading technology for those applications that require a small-scale production. FPGAs can be considered as a technology crossing between hardware and software. Only a small-number of standards for the design of safety-critical systems give guidelines and recommendations that take the peculiarities of the FPGA technology into consideration. The main contribution of this paper is an overview of the existing design standards that regulate the design and verification of FPCA-based systems in safety-critical application fields. Moreover, the paper proposes a survey of significant published research proposals and existing industrial guidelines about the topic, and collects and reports about some lessons learned from industrial and research projects involving the use of FPGA devices.

关键词： design verification electronic design safety-critical system SRAM-based FPGA

Transition Modelling Implications in the CFD Analysis of a Turbine Nozzle Vane Cascade Tested Over a Range of Mach and Reynolds Numbers

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Journal of Thermal Science 2015年第6期24卷 526-534页

作者： Michele Marconcini Roberto Pacciani andrea Arnone University of Florence Department of Industrial Engineering Via Santa Marta

The aerodynamic performance of a gas turbine nozzle vane cascade was investigated over a range of Mach and Reynolds *** work is part of a vast research project aimed at the analysis of fluid dynamics and heat transfer phenomena in cooled *** this paper computed results on the"solid vane"(without cooling devices)are presented and discussed in comparison with experimental *** measurements were provided by the University of Bergamo where the experimental campaign was carried out by means of a subsonic wind *** impact of boundary layer transition is investigated by using a novel laminar kinetic energy transport model and the widely used Langtry-Menterγ-Reθ,t *** comparison between calculations and measurements is presented in terms of blade loading distributions,total pressure loss coefficient contours downstream of the cascade,and velocity/turbulence-intensity profiles within the boundary layer at selected blade surface locations at *** will be shown how transitional calculations compare favorably with experiments.

关键词： Gas turbine CFD validation transition model secondary flows

Novel Galectin-3 interactions involved in oligodendroglial differentiation make inroads into therapeutic strategies for demyelinating diseases

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Neural Regeneration Research 2021年第2期16卷 289-290页

作者： Laura andrea Pasquini Department of Biological Chemistry School of Pharmacy and BiochemistryInstitute of Biological Chemistry and Physicochemistry(IQUIFIB)University of Buenos Aires and National Research Council(CONICET)Buenos AiresArgentina

Galectins(Gals)constitute a 15-member class ofβ-galactoside-binding lectins which recognize *** lacking specific receptors,Gals form multivalent complexes with cell surface glycoconjugates containing suitable oligosaccharides and thus trigger intracellular signals to regulate cell survival and *** are classified into three groups on the basis of their structural architecture:proto,chimera and tandem types。

关键词： spite complexes strategies

l_(1)-based calibration of POD-Galerkin models of two-dimensional unsteady flows

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Chinese Journal of Aeronautics 2021年第1期34卷 226-236页

作者： Riccardo RUBINI Davide LASAGNA andrea DA RONCH Faculty of Engineering and Physical Sciences University of SouthamptonSouthampton SO171BJUnited Kingdom

This paper discusses a physics-informed methodology aimed at reconstructing efficiently the fluid state of a ***,the generation of an accurate reduced order model of twodimensional unsteady flows from data leverages on sparsity-promoting statistical learning *** cornerstone of the approach is l_(1) regularised regression,resulting in sparselyconnected models where only the important quadratic interactions between modes are *** original dynamical behaviour is reproduced at low computational costs,as few quadratic interactions need to be *** approach has two key ***,interactions are selected systematically as a solution of a convex optimisation problem and no a priori assumptions on the physics of the flow are ***,the presence of a regularisation term improves the predictive performance of the original model,generally affected by noise and poor data *** cases are for two-dimensional lid-driven cavity flows,at three values of the Reynolds number for which the motion is chaotic and energy interactions are scattered across the *** is found that:(A)the sparsification generates models maintaining the original accuracy level but with a lower number of active coefficients;this becomes more pronounced for increasing Reynolds numbers suggesting that extension of these techniques to real-life flow configurations is possible;(B)sparse models maintain a good temporal stability for *** methodology is ready for more complex applications without modifications of the underlying theory,and the integration into a cyberphysical model is feasible.

关键词： Computational methods Dynamical systems Lid-driven cavity L_(1)-based regression Reduced order models Sparsification Stabilization of ROMs

New oral agents for erectile dysfunction: what is changing in our practice?

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Asian Journal of Andrology 2001年第3期3卷 175-179页

作者： Antonio Aversa andrea Fabbri AFaR-CRCC Fatebenefratelli-Isola Tiberina Hospital and Endocrinology Unit Department of Internal Medicine University of Rome 'Tor Vergata' 00133 Rome ItalyEndocrinology Unit Department of Internal Medicine University of Rome 'Tor Vergata' 00133 Rome Italy

Erectile dysfunction (ED) is a highly prevalent disorder affecting an estimated 152 million men worldwide and isassociated with a variety of behavioral risk factors, such as cigarette smoking and excessive alcohol consumption, aswell as numerous age - related medical conditions, notably type-2 diabetes mellitus and cardiovascular disease. A ratio-nal step - wise approach which includes comprehensive medical and sexual history, a focused physical examination andessential laboratory tests such as fasting glucose, lipid profile and testosterone assay is to be preferred. Current diagnos-tic work - up does not recommend any of the specialized tests which were previously considered mandatory-i. e. penilepharmacotesting, Duplex ultrasound and nocturnal penile tumescence. Hormonal replacement therapy is appropriate onlyin the hypogonadal male with ED. Prior to direct intervention, the physician should consider altering modifiable riskfactors or causes, although frequently insufficient to reverse ED completely. When indicated, oral therapy with newmolecules (phosphodiesterase inhibitors or apomorphine) is the first - line treatment for the majority of patients becauseof potential benefits and lack of invasiveness. (Asian J Androl 2001 Sep; 3: 175-179 )

关键词： erectile dysfunction oral medicine therapy phosphodiesterase inhibitors apomorphine nitric oxide